Dans ce travail, on a mené une étude numérique de la convection naturelle laminaire stationnaire dans une enceinte carrée chauffée par une section carrée et remplie d’un mélange d’eau et des nanoparticules. Les équations gouvernantes ont été discrétisées par la méthode des volumes finis en utilisant un schéma hybride. Un code de calcul a été conçu et réalisé dans ce contexte pour utiliser la simulation numérique comme outil d’investigation. Les résultats sont analysés à travers les champs thermique et dynamique avec une attention particulière au nombre de Nusselt. Ce travail a été validé en comparant à ceux de la littérature en modifiant légèrement la configuration étudiée. Une étude paramétrique a été menée en considérant le nombre de Rayleigh, le type de nanofluide.

The wireless sensor networks (WSN) are particularly vulnerable to various attacks at different layers of the protocol stack. Many intrusion detection system (IDS) have been proposed to secure WSNs. But all these systems operate in a single layer of the OSI model, or do not consider the interaction and collaboration between these layers. Consequently these systems are mostly inefficient and would drain out the WSN. In this paper we propose a new intrusion detection system based on cross layer interaction between the network, Mac and physical layers. Indeed we have addressed the problem of intrusion detection in a different way in which the concept of cross layer is widely used leading to the birth of a new type of IDS. We have experimentally evaluated our system using the NS simulator to demonstrate its effectiveness in detecting different types of attacks at multiple layers of the OSI model.

This paper presents an Enhanced version of the Embedded Zerotree Wavelet (EEZW) dedicated to Phonocardiogram (PCG) compression. This algorithm is constituted of six steps: applying Discrete Wavelet Transform, uniform scalar quantizing, creating dominant and subordinate lists, generating preliminary symbol stream and finally using arithmetic coding. The compression algorithm has been tested and evaluated by its application on several databases. The adapted 1-D algorithm shows better performance than the original EZW, the modified Ouafi’s EZW (MEZW) and the popular MP3 audio-specific format, regarding to the well-known trade-off rate/distortion. Also a low computational complexity of our method is obtained. It is due to the only one time subordinate pass calculated one time after the achievement of all dominant passes.

This paper presents a study on the performances of distance relays setting in 400 kV in Eastern Algerian transmission networks at Sonelgaz Group (Algerian Company of Electricity) compensated by shunt Flexible AC Transmission System (FACTS). The facts are used for controlling transmission voltage, power flow, reactive power, and damping of power system oscillations in high power transfer levels. The direct impacts of SVC devices, i.e. Thyristor Controlled Reactor (TCR) and the Thyristor Switched Capacitors (TSC) insertion on the total impedance of a transmission line (ZAB) protected by MHO distance relay, are investigated. The modified setting zones protections (Z1, Z2 and Z3) have been calculated in order to improve the performances of distance relay protection and prevent circuit breaker nuisance tripping. The simulation results are performed in MATLAB software and show the direct impact of the thyristors firing angle (α) and substance on the total impedance of the protected line.

This paper addresses the problem of the detection of new failures modes in industrial plants. Since its associated optimization problem is NP-hard, an efficient method based on taboo search and Bezdeck criterion is proposed, intensification and diversification strategies are also included because of the non connectivity of the solutions space. The proposed approach exercised on a simulated industrial system was shown to exhibit good performances in dealing with the occurrence of new faults in industrial processes, despite that such search algorithm is perfectly general, it can be easily extended to more complicated schemes.

La compétitivité des entreprises industrielles n’est plus à démontrer et tout le monde s’accorde que l’innovation technologique est le facteur déterminant pour la survie des
entreprises. Mais force de constater que c’est aussi ce même facteur qui fait défaut pour les entreprises des Pays En Voie de développement (PVD).
L’innovation, qui reste la barrière infranchissable, est à la fois la cause et la conséquence d’absence relative du facteur technologique dans les démarches stratégiques de ces entreprises.
Mais, avec la pénétration massive des Technologies de l’Information et de la Communication (TIC) dans la vie des entreprises, une nouvelle approche du transfert de technologie permet aux
entreprises de se maintenir au fait des derniers développements technologiques dans leurs secteurs d’activités, d’identifier les différentes menaces qui les entourent et de découvrir les
occasions à saisir.
La veille stratégique, qui occupe une place de choix dans cette nouvelle approche, fera l’objet de cette étude où l’on proposera une démarche d’implantation de cette activité dans une
cimenterie algérienne qu’est connue comme étant une industrie à transfert de technologie « clés en main ».

his paper presents a combined experimental and theoretical investigation and proposes a mechanical load modeling of a multidirectional layer CFRP drilling to avoid fibers delamination by a better choice of their orientations. A first step consists in working with unidirectional CFRP to correlate cutting mode (opening, shear and bending) with force level depending on the angular tool position. The discretisation of the cutting edge is employed to know the exact contribution of each elementary part of the edge, resulting in a complete drill operation modeling (tip penetration, full engagement and exit). A second step consists in using this unidirectional approach to model a multidirectional layer CFRP drilling. In this case, layers are cut simultaneously which induce brutal mechanical load variation. A summation method is used to estimate the force level depending on fiber arrangement. Optimal orientation combinations are underlined by this approach, in order to improve the CFRP design, by considering the manufacturing concerns.